Diabetes mellitus, a disorder resulting from the absolute (Type 1) or relative (Type 2) deficiency of insulin, affects approximately 6 percent of the U.S. population; the associated micro- and macrovascular complications makes this disease one of the leading causes of morbidity and mortality. The long term objective of this proposal is to understand the role that cell type specific gene transcription plays in the differentiation of the insulin-producing beta-cell of the pancreas. The information gathered from such studies should make it possible to reprogram various cell types in order to treat the cellular and genetic deficiencies occurring in diabetes. The general strategy to use the transcription factor Nkx6.1 as a paradigm for a beta-cell restricted transcription factor that is necessary to direct cell differentiation and proliferation. The focus of this proposal is to functionally characterize the transcription factor Nkx6.1 and to identify genes that are directly and indirectly regulated by this factor during the process of beta-cell differentiation. The specific aims of this proposal are: 1. Biochemically characterize Nkx6.1 with respect to its DNA binding properties 2. Characterize the functional activation domains of Nkx6.1 3. Identify and characterize target genes for Nkx6.1 action To achieve these aims, we will utilize in vitro biochemical assays of protein/DNA binding, transient mammalian cell transfections, transgenic mouse models, and cDNA subtraction/differential display. Taken together, the knowledge gained from these studies will provide insight into the mechanisms governing beta-cell differentiation in the developing pancreas. This information can eventually be applied to engineering new beta-cells for patients with diabetes.